# Define the system of units to use internally.
InternalUnitSystem:
UnitMass_in_cgs: 1 # Grams
UnitLength_in_cgs: 1 # Centimeters
UnitVelocity_in_cgs: 1 # Centimeters per second
UnitCurrent_in_cgs: 1 # Amperes
UnitTemp_in_cgs: 1 # Kelvin
# Values of some physical constants
PhysicalConstants:
G: 6.67408e-8 # (Optional) Overwrite the value of Newton's constant used internally by the code.
# Cosmological parameters
Cosmology:
h: 0.6777 # Reduced Hubble constant
a_begin: 0.0078125 # Initial scale-factor of the simulation
a_end: 1.0 # Final scale factor of the simulation
Omega_m: 0.307 # Matter density parameter
Omega_lambda: 0.693 # Dark-energy density parameter
Omega_b: 0.0455 # Baryon density parameter
Omega_r: 0. # (Optional) Radiation density parameter
w_0: -1.0 # (Optional) Dark-energy equation-of-state parameter at z=0.
w_a: 0. # (Optional) Dark-energy equation-of-state time evolution parameter.
# Parameters for the hydrodynamics scheme
SPH:
resolution_eta: 1.2348 # Target smoothing length in units of the mean inter-particle separation (1.2348 == 48Ngbs with the cubic spline kernel).
CFL_condition: 0.1 # Courant-Friedrich-Levy condition for time integration.
h_tolerance: 1e-4 # (Optional) Relative accuracy of the Netwon-Raphson scheme for the smoothing lengths.
h_max: 10. # (Optional) Maximal allowed smoothing length in internal units. Defaults to FLT_MAX if unspecified.
max_volume_change: 1.4 # (Optional) Maximal allowed change of kernel volume over one time-step.
max_ghost_iterations: 30 # (Optional) Maximal number of iterations allowed to converge towards the smoothing length.
initial_temperature: 0 # (Optional) Initial temperature (in internal units) to set the gas particles at start-up. Value is ignored if set to 0.
minimal_temperature: 0 # (Optional) Minimal temperature (in internal units) allowed for the gas particles. Value is ignored if set to 0.
H_mass_fraction: 0.76 # (Optional) Hydrogen mass fraction used for initial conversion from temp to internal energy.
# Parameters for the self-gravity scheme
Gravity:
eta: 0.025 # Constant dimensionless multiplier for time integration.
theta: 0.7 # Opening angle (Multipole acceptance criterion)
comoving_softening: 0.0026994 # Comoving softening length (in internal units).
max_physical_softening: 0.0007 # Physical softening length (in internal units).
a_smooth: 1.25 # (Optional) Smoothing scale in top-level cell sizes to smooth the long-range forces over (this is the default value).
r_cut_max: 4.5 # (Optional) Cut-off in number of top-level cells beyond which no FMM forces are computed (this is the default value).
r_cut_min: 0.1 # (Optional) Cut-off in number of top-level cells below which no truncation of FMM forces are performed (this is the default value).
# Parameters for the task scheduling
Scheduler:
nr_queues: 0 # (Optional) The number of task queues to use. Use 0 to let the system decide.
cell_max_size: 8000000 # (Optional) Maximal number of interactions per task if we force the split (this is the default value).
cell_sub_size_pair_hydro: 256000000 # (Optional) Maximal number of interactions per sub-pair hydro task (this is the default value).
cell_sub_size_self_hydro: 32000 # (Optional) Maximal number of interactions per sub-self hydro task (this is the default value).
cell_sub_size_pair_grav: 256000000 # (Optional) Maximal number of interactions per sub-pair gravity task (this is the default value).
cell_sub_size_self_grav: 32000 # (Optional) Maximal number of interactions per sub-self gravity task (this is the default value).
cell_split_size: 400 # (Optional) Maximal number of particles per cell (this is the default value).
max_top_level_cells: 12 # (Optional) Maximal number of top-level cells in any dimension. The number of top-level cells will be the cube of this (this is the default value).
tasks_per_cell: 0 # (Optional) The average number of tasks per cell. If not large enough the simulation will fail (means guess...).
mpi_message_limit: 4096 # (Optional) Maximum MPI task message size to send non-buffered, KB.
# Parameters governing the time integration (Set dt_min and dt_max to the same value for a fixed time-step run.)
TimeIntegration:
time_begin: 0. # The starting time of the simulation (in internal units).
time_end: 1. # The end time of the simulation (in internal units).
dt_min: 1e-6 # The minimal time-step size of the simulation (in internal units).
dt_max: 1e-2 # The maximal time-step size of the simulation (in internal units).
# Parameters governing the snapshots
Snapshots:
basename: output # Common part of the name of output files
time_first: 0. # Time of the first output (in internal units)
delta_time: 0.01 # Time difference between consecutive outputs (in internal units)
compression: 0 # (Optional) Set the level of compression of the HDF5 datasets [0-9]. 0 does no compression.
UnitMass_in_cgs: 1 # (Optional) Unit system for the outputs (Grams)
UnitLength_in_cgs: 1 # (Optional) Unit system for the outputs (Centimeters)
UnitVelocity_in_cgs: 1 # (Optional) Unit system for the outputs (Centimeters per second)
UnitCurrent_in_cgs: 1 # (Optional) Unit system for the outputs (Amperes)
UnitTemp_in_cgs: 1 # (Optional) Unit system for the outputs (Kelvin)
# Parameters governing the conserved quantities statistics
Statistics:
delta_time: 1e-2 # Time between statistics output
energy_file_name: energy # (Optional) File name for energy output
timestep_file_name: timesteps # (Optional) File name for timing information output. Note: No underscores "_" allowed in file name
# Parameters related to the initial conditions
InitialConditions:
file_name: SedovBlast/sedov.hdf5 # The file to read
generate_gas_in_ics: 0 # (Optional) Generate gas particles from the DM-only ICs (e.g. from panphasia).
cleanup_h_factors: 0 # (Optional) Clean up the h-factors used in the ICs (e.g. in Gadget files).
cleanup_smoothing_lengths: 0 # (Optional) Clean the values of the smoothing lengths that are read in to remove stupid values. Set to 1 to activate.
smoothing_length_scaling: 1. # (Optional) A scaling factor to apply to all smoothing lengths in the ICs.
shift_x: 0. # (Optional) A shift to apply to all particles read from the ICs (in internal units).
shift_y: 0.
shift_z: 0.
replicate: 2 # (Optional) Replicate all particles along each axis a given integer number of times. Default 1.
# Parameters controlling restarts
Restarts:
enable: 1 # (Optional) whether to enable dumping restarts at fixed intervals.
save: 1 # (Optional) whether to save copies of the previous set of restart files (named .prev)
onexit: 0 # (Optional) whether to dump restarts on exit (*needs enable*)
subdir: restart # (Optional) name of subdirectory for restart files.
basename: swift # (Optional) prefix used in naming restart files.
delta_hours: 6.0 # (Optional) decimal hours between dumps of restart files.
stop_steps: 100 # (Optional) how many steps to process before checking if the /stop file exists. When present the application will attempt to exit early, dumping restart files first.
# Parameters governing domain decomposition
DomainDecomposition:
initial_type: simple_metis # (Optional) The initial decomposition strategy: "grid",
# "simple_metis", "weighted_metis", or "vectorized".
initial_grid_x: 10 # (Optional) Grid size if the "grid" strategy is chosen.
initial_grid_y: 10 # ""
initial_grid_z: 10 # ""
repartition_type: costs/costs # (Optional) The re-decomposition strategy, one of:
# "none/none", "costs/costs", "counts/none", "none/costs", "counts/costs",
# "costs/time" or "none/time".
# These are vertex/edge weights with "costs" as task timing, "counts" as
# sum of particles and "time" as the expected time of the next updates
trigger: 0.05 # (Optional) Fractional (<1) CPU time difference between MPI ranks required to trigger a
# new decomposition, or number of steps (>1) between decompositions
minfrac: 0.9 # (Optional) Fractional of all particles that should be updated in previous step when
# using CPU time trigger
# Parameters related to the equation of state ------------------------------------------
EoS:
isothermal_internal_energy: 20.26784 # Thermal energy per unit mass for the case of isothermal equation of state (in internal units).
# Parameters related to external potentials --------------------------------------------
# Point mass external potentials
PointMassPotential:
position_x: 50. # location of external point mass (internal units)
position_y: 50.
position_z: 50.
mass: 1e10 # mass of external point mass (internal units)
timestep_mult: 0.03 # Dimensionless pre-factor for the time-step condition
# Isothermal potential parameters
IsothermalPotential:
position_x: 100. # Location of centre of isothermal potential with respect to centre of the box (internal units)
position_y: 100.
position_z: 100.
vrot: 200. # Rotation speed of isothermal potential (internal units)
timestep_mult: 0.03 # Dimensionless pre-factor for the time-step condition
epsilon: 0.1 # Softening size (internal units)
# Disk-patch potential parameters
DiscPatchPotential:
surface_density: 10. # Surface density of the disc (internal units)
scale_height: 100. # Scale height of the disc (internal units)
z_disc: 400. # Position of the disc along the z-axis (internal units)
z_trunc: 300. # (Optional) Distance from the disc along z-axis above which the potential gets truncated.
z_max: 380. # (Optional) Distance from the disc along z-axis above which the potential is set to 0.
timestep_mult: 0.03 # Dimensionless pre-factor for the time-step condition
growth_time: 5. # (Optional) Time for the disc to grow to its final size (multiple of the dynamical time)
# Sine Wave potential
SineWavePotential:
amplitude: 10. # Amplitude of the sine wave (internal units)
timestep_limit: 1. # Time-step dimensionless pre-factor.
growth_time: 0. # (Optional) Time for the potential to grow to its final size.
# Parameters related to cooling function ----------------------------------------------
# Constant du/dt cooling function
ConstCooling:
cooling_rate: 1. # Cooling rate (du/dt) (internal units)
min_energy: 1. # Minimal internal energy per unit mass (internal units)
cooling_tstep_mult: 1. # Dimensionless pre-factor for the time-step condition
# Constant lambda cooling function
LambdaCooling:
lambda: 2.0 # Cooling rate (in cgs units)
minimum_temperature: 1.0e4 # Minimal temperature (Kelvin)
mean_molecular_weight: 0.59 # Mean molecular weight
hydrogen_mass_abundance: 0.75 # Hydrogen mass abundance (dimensionless)
cooling_tstep_mult: 1.0 # Dimensionless pre-factor for the time-step condition
# Cooling with Grackle 3.0
GrackleCooling:
CloudyTable: CloudyData_UVB=HM2012.h5 # Name of the Cloudy Table (available on the grackle bitbucket repository)
WithUVbackground: 1 # Enable or not the UV background
Redshift: 0 # Redshift to use (-1 means time based redshift)
WithMetalCooling: 1 # Enable or not the metal cooling
ProvideVolumetricHeatingRates: 0 # (optional) User provide volumetric heating rates
ProvideSpecificHeatingRates: 0 # (optional) User provide specific heating rates
SelfShieldingMethod: 0 # (optional) Grackle (<= 3) or Gear self shielding method
OutputMode: 0 # (optional) Write in output corresponding primordial chemistry mode
MaxSteps: 10000 # (optional) Max number of step when computing the initial composition
ConvergenceLimit: 1e-2 # (optional) Convergence threshold (relative) for initial composition
# Parameters related to chemistry models -----------------------------------------------
# EAGLE model
EAGLEChemistry:
InitMetallicity: 0. # Inital fraction of particle mass in *all* metals
InitAbundance_Hydrogen: 0.752 # Inital fraction of particle mass in Hydrogen
InitAbundance_Helium: 0.248 # Inital fraction of particle mass in Helium
InitAbundance_Carbon: 0.000 # Inital fraction of particle mass in Carbon
InitAbundance_Nitrogen: 0.000 # Inital fraction of particle mass in Nitrogen
InitAbundance_Oxygen: 0.000 # Inital fraction of particle mass in Oxygen
InitAbundance_Neon: 0.000 # Inital fraction of particle mass in Neon
InitAbundance_Magnesium: 0.000 # Inital fraction of particle mass in Magnesium
InitAbundance_Silicon: 0.000 # Inital fraction of particle mass in Silicon
InitAbundance_Iron: 0.000 # Inital fraction of particle mass in Iron
CalciumOverSilicon: 0.0941736 # Constant ratio of Calcium over Silicon abundance
SulphurOverSilicon: 0.6054160 # Constant ratio of Sulphur over Silicon abundance